This invention relates to a method for grinding cereal grains, particularly to methods wherein the cereal grain is ground in the presence of an aqueous grinding medium and a polysaccharide.
In the preparation of many food products from cereal grains, the cereal grain is often ground or milled to a suitable size in the presence of a liquid grinding medium, conventionally water or other aqueous liquid. For example, corn, which has previously been heated in an alkaline aqueous solution, e.g., calcium hydroxide solution, is often ground in a rotary shear type apparatus, e.g., hammer mill, to make a ready mix useful for preparing tortillas and other corn products.
In general, due to the inefficiencies inherent in shear type grinding operations, to obtain the desired particle size requires relatively long grinding times and outputs of significant amounts of energy. Moreover, as the kernels of grain are fractured during the grinding process, starches are released. These starches, when contacted with an aqueous grinding medium, form a sticky mass which slows the grinding process even further.
One method of increasing the efficiency of the grinding operation is to reduce the moisture content of the grain prior to grinding. Unfortunately, however, such a method requires significant additional processing time and equipment costs and greatly slows the overall milling operation. Moreover, the dried flour prepared in this manner has a low moisture content, which deleteriously affects the properties of doughs and products prepared therefrom.
Grinding aids, e.g., silicates, phosphonates and sulfonates have been found useful in increasing the efficiency of the impact grinding of inorganic ores and fossilized mineral ores, but such grinding aids have not generally been found to effectively improve the grinding of the more plastic (i.e., easily deformed) cereal grains. Specifically, relatively large amounts of such conventional grinding aids are generally required to obtain the desired grinding efficiency. In addition, such grinding aids often deleteriously affect the subsequent processing of the ground material and are not generally approved for food usage. Therefore, they must normally be separated from the ground cereal grain following grinding.
In view of the aforementioned problems associated with the prior art, it would be highly desirable to improve the efficiency of the grinding of cereal grains.